This relates generally to electronic devices and, more particularly, to power protection circuitry for electronic devices.
Electronic devices such as cellular telephones, media players, tablet computers, and other devices are often coupled to accessories. For example, an accessory device may have a keyboard, display, speakers, or other components that can be connected to a host electronic device for use in receiving inputs from or outputting content to a user.
During normal operation, the host device may supply power to the accessory. If the accessory is improperly connected to the host device, such as when the power supply ports are inadvertently inverted, a high voltage can be delivered to ground power supply port of the accessory while a low voltage can be delivered to a positive power supply port of the accessory. In such scenarios, it may be desirable to decouple the incorrectly connected power supply path between the host device and the accessory to prevent damaging the internal circuitry within the accessory. This problem becomes even more challenging to solve when there are other data ports in additional to the power and ground power supply ports coupled between the host device and the accessory.
It would therefore be desirable to be able to provide improved voltage protection circuitry for preventing damage from reverse voltage when accessories are coupled to the electronic device.